Results 201 to 210 of about 31,775 (244)
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Hormonal regulation of spermatid binding
Journal of Cell Science, 1991ABSTRACT A Sertoli-spermatid coculture model is described in which a large percentage (>76%) of round spermatids remain viable for 48 h and bind to Sertoli cells. The effects of follicle-stimulating hormone (FSH) and testosterone on spermatid binding (expressed as the spermatid density; SD- the number of spermatids per unit area ...
D F, Cameron, K E, Muffly
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Nuclear shaping in marsupial spermatids
Journal of Ultrastructure Research, 1972Nuclear shaping was investigated in two species of American opossum, Didelphus virginiana and Marmosa mitus. The mature spermatozoan head achieves its “U” shaped form by the progressive flattening of the posterior margin of the nucleus and the development of a protrusion on one side of the nucleus.
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Microtubules in the spermatids of stick insects
Journal of Ultrastructure and Molecular Structure Research, 1988Spermatids from two phasmid species were seen to possess an unusually large amount of microtubules along the nucleus and tail. Some of the microtubules have a loosely fitting sleeve for half a micron or more. During late stages in spermiogenesis the microtubules aggregate and form one or several "microtubular crystals" consisting of electron-lucid ...
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Mouse Round Spermatid Injection
Journal of Visualized ExperimentsRound spermatids, characterized by their haploid genetic content, represent the precursor cells to mature spermatozoa. Through the innovative technique of round spermatid injection (ROSI), oocytes can be successfully fertilized and developed into viable fetuses. In a groundbreaking milestone achieved in 1995, the first mouse fetus was born through ROSI
Haibo, Zhu +6 more
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Intranuclear whorls in the hamster spermatid
Journal of Ultrastructure Research, 1969In the 2-week-old hamster, intranuclear whorls were observed in cells located among the spermatids. The whorls, measuring up to 2.5 μ in diameter, were composed of sheets of microtubules. The distance between the individual sheets was 150 A, the tubular lumen was 80 A, and the tubular wall measured 120 A. It is assumed that the presence of intranuclear
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Centrioles in the Spermatids of Insects1
Annals of the Entomological Society of America, 1968The University of Texas at Austin There have been many statements published regarding the number of centrioles in the spermatids of insects. Some earlier workers reported the occurrence of 2 centrioles in several groups of insects, although only one was seen in the spermatids of some species (summarized in Wilson 1928).
Osmond P. Breland +3 more
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1987
The two maturation divisions of each spermatocyte result in four haploid cells, spermatids. These differentiate into spermatozoa, a process called spermiogenesis which ends when the spermatozoa are released from the seminiferous epithelium. After the haploid round spermatids are formed, their nuclear and cytoplasmic components undergo a complex series ...
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The two maturation divisions of each spermatocyte result in four haploid cells, spermatids. These differentiate into spermatozoa, a process called spermiogenesis which ends when the spermatozoa are released from the seminiferous epithelium. After the haploid round spermatids are formed, their nuclear and cytoplasmic components undergo a complex series ...
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Ultrastructural Characteristics of Idiopathic Spermatidic Arrest
Archives of Andrology, 1979Previous studies on some cases of idiopathic spermatidic arrest showed an anomaly in glucose metabolism, in particular decreased utilization of glycogen at stage 3 of spermatogenesis, when condensation of the spermatid head commences. Histological patterns seen on light microscopy confirmed the reduced utilization of glycogen at stage 3 of ...
M, Re +4 more
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Glycogen in Spermatidic Arrest
1971Glycogen probably plays an important role in the maturation of germinal cells. Intratubular glycogen is abundant in the prepubertal stage; it diminishes remarkably at the beginning of puberty, reappears during the period of complete sexual maturation and the highest increase is found in the tubules in involution.
A. Fabbrini, M. Re, M. Savioli, G. Spera
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